Grace Spencer b. 27 Jul 1674 in East Haddam, Connecticut, daughter of Samuel Spencer and Hannah Willey, is named by several sources as the wife of John Day, Jr., among them Ancestors and Descendants of Andrew Lee and Clarinda Knapp Allen by Gerald R. Fuller, 1952; Genealogical Notes, First Settlers of Connecticut and Massachusetts, by Nathaniel Goodwin, 1982; and The Abridged Compendium of American Genealogy ed. Frederick A. Virkus (1968).

However, in his article "The Four Spencer Brothers -- Their Ancestors and Descendants", The American Genealogist 27, April 1951, Donald Lines Jacobus pointed out that the absence of this Grace Spencer from her father's will strongly suggests that she died young. Jacobus says that the Grace Spencer who married John Day was the one who was baptised 24 Sep 1676 in East Haddam, a daughter of John Spencer and Rebecca Hayward, and that she was a cousin to the other Grace Spencer. It is also this Grace Spencer that is given as John Day's wife in Jacobus and Waterman's Hale, House and Related Families.

[S389] Donald Lines Jacobus, "The Four Spencer Brothers -- Their Ancestors and Descendants." The American Genealogist 27:79, April 1951.

[S101] The Great Migration Begins: Immigrants to New England, 1620-1633, Volumes 1-3 and The Great Migration: Immigrants to New England,1634-1635, Volumes 1-7, by Robert Charles Anderson. Boston: New England Historic Genealogical Society, 1996-2011., "by 1666".